Arc furnaces are often used in the steel industry, for example for melting scrap or sponge iron, while it is also possible for other metals to be smelted in an arc furnace. An arc furnace is based on the conversion of electrical energy into thermal energy, using the arc principle. Power outputs of up to 200 MW and more are thereby generated.
An arc furnace may be designed as a DC furnace (generally with one electrode) or as an AC furnace (generally with three electrodes).
A steel processing plant may also comprise a number of such arc furnaces. For example, the actual arc furnace, in which the melting takes place, is often followed by a ladle furnace, which is also designed as an arc furnace. The ladle is the transporting vessel into which the liquid metal is filled from the arc melting furnace. In the ladle furnace, quality-enhancing additives are added, for example, or a further treatment is carried out.
The automation of an arc furnace installation requires many functions to be taken into consideration. The furnace control, for activating the basic functions of the furnace, the electrode control, by means of which the length and power of the arc are ultimately set, and the melting control may be mentioned here by way of example. For all of these functions, a programmable controller is respectively provided. Whenever an arc furnace installation is realized, these programmable controllers must be laboriously tested and adapted to one another each time with respect to interfaces and satisfactory interaction. The associated expenditure on hardware is relatively high and higher expenditure in terms of assembly and initial operation is incurred, since a number of programmable controllers with their own switch cabinets have to be installed.